Doesn't matter about the flywheel if you haven't addressed the low 105 psi compression reading! This can be the main problem you're having!!

 

More compression determines timing?? It sparks about 3 inches to the right of timing marks. Not trying to be thick headed about this but isn't making sense when it starts and runs on 1st or 2nd pull but other flywheels cause kickback. Thanks

 

You can't adjust or determine timing this way!! It must be running(and still cold) and with a timing light and rpm/dwell meter @ a steady 3000 rpms,then the center mark (25 degree) should line up or close with the case pointer. You have to do this quickly as timing will alter as the engine gets warm.This is from the manual.